Bolt-in connector



Jan. 31, 1967 R. c. HUDSON 9 3 BOL'I IN CONNECTOR Filed Oct. 30, 1964 2 Sheets$heet l //vv/vr0/2. R OBERT C, HuosoN ATTORNEY Jan. 31, 1967 Filed 001.. 30, 1964 R. C. HUDSON BOLT-IN CONNECTOR 2 Sheets-$heet 2 BYKMjC/ae7 ROBERT CHuosow I United States Patent 3,302,158 BOLT-IN CONNECTOR Robert C. Hudson, Panorama City, Calif., assignor to General Electric Company, a corporation of New York Filed Oct. 30, 1964, Ser. No. 407,772 7 Claims. (Cl. 339-22) This invention relates to contact assemblies and particularly to stab contact assemblies of the male type for boltin engagement with conductors such as bus bars, and it has for an object the provision of a simple, reliable and inexpensive contact assembly of this character.

More specifically, the invention relates to contact assemblies in which bus bars are mounted in insulating enclosures which are provided with plug-in openings aligned with stab contact receiving slots in the bus bars, and a further object of the invention is the provision of fastening means that are insertable through the plug-in opening in the insulating enclosures and through the aligned contact receiving slots in the bus bars and including means for firmly fastening the male stab connector contacts of a contact assembly to the bus bars by a bolt-in action.

Heretofore, bus bars have been provided with slots for receiving male type spring-biased stab contacts for plug-in engagement with the bus bars. Another object of this invention is the provision of a fastening means of the bolt-in type which makes use of such slots in the bus bars and does not require any extra drilling in the bus bars to effect a bolt-in connection.

In certain types of electrical apparatus such, for example, as motor control centers, a number of apparatus units are mounted within a cabinet having a bus assembly disposed atthe rear. Another object of the invention is the provision of a fastening means for an electrical apparatus assembly or control unit of the type making a bolted connection at the back of the unit, which nevertheless can be made and tightened from the front of the unit.

Still another object of the invention is the provision of a fastening means for a bolt-in type of connector in which force on the connector in the pull-out direction produces an increase in the force that secures the connector to the bus bar.

In carrying the invention into effect in one form thereof, a bolt-in type connector male stab contact is provided having a contact portion, a terminal portion, and an intermediate portion, for making electrical connection between a unit of electrical apparatus and a bus bar provided with a slot for receiving the male stab contact. Means is provided for forcing a surface of the contact portion of the connector bar into engagement with an edge surface of the slot in the bus bar, and for preventing withdrawal of the bar from the slot. This means comprises a bolt extending through the intermediate portion of the connector bar parallel to the contact portion, with a threaded end projecting through the slot in the bus bar. A nut on the threaded end of the bolt engages the leading end of the contact portion of the connector and is thereby restrained from turning. Turning the bolt tightens the nut and forcefully wedges it between a surface of the contact portion of the connector and an edge surface of the slot.

For a. better and more complete understanding of the invention, reference should now be had to the following specification and to the accompanying drawings of which:

FIGURE 1 is a view in perspective of a compartment of an apparatus cabinet or motor control center incorporating the invention, an apparatus unit subassernbly or control unit being shown in displaced condition;

FIGURE 2 is a sectional view of a portion of the apparatus of FIGURE 1, the control unit being shown in fully mounted position;

FIGURE 3 is a front view of the portion of the apparatus shown in FIGURE 2, and

FIGURE 4 is a side view of the portion of the apparatus illustrated in FIGURE 2.

Referring now to the drawings, a stationary cabinet 10 is provided for mounting and housing a plurality of control apparatus subassemblies such as 13, comprising electrical devices such, for example, as motor starters and circuit breakers. Such a cabinet usually has a plurality of vertically disposed compartments. Since the compartments are similar, only the compartment 11 is illustrated in the drawing. The cabinet has a vertical bus bar assembly 12 which extends substantially the full height of the cabinet and passes through each of the compa-rtments.

The apparatus unit 13 is adapted to be inserted and withdrawn from the compartment 11 for connection to and disconnection from the bus bar assembly. The apparatus unit 13 when inserted in compartment 11 is sup-. ported on a horizontal shelf 14 which separates compartment 11 from a similar compartment disposed beneath it. The apparatus unit 13 includes one or more electrical devices 15 and 16 and line and load contact terminal blocks 17 and 18, respectively, connected to the devices. The line contact terminal block 17 is adapted to be electrically connected to the bus bars of the bus assembly 12 by means of the novel connector of the present invention.

The cabinet 10 includes a pair of spaced apart parallel side panels 19 and 20. For supporting the bus assembly 12, a pair of structural members 21 are secured to the side panels 19 and 20 at areas adjacent the rear of the cabinet and extend substantially the full height thereof. A pair of generally Z-shaped mounting plates or brackets 22 are secured to the channel members 21. Mounted between the members 21 on the rearwardly offset co-planar end portions of the members 22, is the bus assembly 12. The bus assembly 12. comprises a pair of identically configured insulation members 23 and 24, each of which is preferably an integral unit extending substantially the full height of the housing. The insulating members 23 and 24 are illustrated in FIGURES l and 2 as having three vertically extending horizontally spaced apart recesses and as being mounted in face to face relationship to provide three composite generally tubular enclosures 25, 26

and 27. Mounted within these enclosures are three bus bars 28, 29 and 30 of a three-phase electrical system which extend vertically substantially the full height of the cabinet.

As shown in FIGURE 2 the bus bars 28, 2? and 30 include slots 28a, 29a and 30a for receiving the contact portions of connector bars 31, 32 and 33 carried by the connector assembly block 17. The slots 28a, 29a and 30a are horizontally aligned in each compartment of the cabinet and the corresponding slots in each bus bar in all of the compartments are vertically aligned. Each of the tubular insulating members 25, 26 and 27 is provided with a plurality of plug-in openings each in alignment with the corresponding slot in the bus bar mounted in such tubular member. Thus in the compartment 11, the tubular insulating members 25, 26 and 27 are provided with plugin openings 35, 36 and 37 aligned with slots 28a, 29a and 36a, respectively in bus bars 28, 29 and 30.

As best shown in FIGURE 1, the apparatus unit 13 includes a mounting plate or saddle 38 of generally L-shaped configuration having a vertically extending rear wall 39 which supports on its forward face the connector assembly block 17. The horizontally extending portion 390 of the saddle 38 is adapted for sliding engagement with the horizontal shelf 14 when the apparatus unit is inserted in the compartment 11.

Although the connector bars 31, 32 and 33 are not identical, they are generally similar; consequently only the bar 33 will be described in detail. (See FIG. 2.) It has an elongated contact portion 33a extending out behind the rear wall 39 of the unit, a terminal portion 33b and an intermediate portion 330. The broad flat faces of the contact portion and the terminal portion are disposed in parallel planes. The broad flat faces of the intermediate portion 330 are disposed perpendicular to the parallel planes of the contact portion and the terminal portion. The end of the terminal portion 33b is bent at right-angles and is provided wtih a threaded hole 33d receiving a threaded fastening screw 40. A hole 33c is provided in the intermediate portion 330 adjacent the bend line between it and contact portion 33a. An elongated screw bolt 43 passes through the hole 33c and extends in a direction parallel to the contact portion and adjacent thereto. Similar screw bolts 41 and 42 pass through openings in the intermediate portions of connector bars 31 and 32 and extend parallel to their contact portions.

The connector bar assembly block 17 is made of a suitable material such as molded insulation, and includes three spaced apart integral bosses 44, 45 and 46. The spacing of these bosses corresponds to the spacing of the bus bars 28, 29 and 30 in the busway. Extending from the opposite surface of the block 17 are two spaced apart integral bosses 47 and 48. For the purpose of mounting the connector bars 31, 32 and 33 and their associated screw bolts 41, 42 and 43, respectively in the connector bar assembly block, three apertures 44a, 45a and 46a are provided, which extend through the base 17 at bosses 44, 45 and 46 respectively. Each of the apertures 44a, 45a, and 46a has a generally T-shaped cross section. Each of the connector bars 31, 32, 33, is mounted in the portion of the aperture which constitutes the crossbar of the T configuration and each of the screw bolts 41, 42, 43, is mounted in the portion that constitutes the stem of the T configuration.

Recesses are provided in the front surface of the block 17 receiving the intermediate portions of the connector bars 31, 32 and 33 so that these portions are flush with the corresponding surface of the base 17. The bars 31, 32, 33 are retained on the block 17 by means of pins 31 32f, 33 which are frictionally retained in corresponding holes in the bars respectively.

Fastening screws 54 and 55 are provided, passing through the block 17, and having their heads seated in recesses 52, 53 respectively, and serve to fasten the block 17 to the saddle 38.

After the connector bars 31, 32 and 33 and their associated screw bolts 41, 42 and 43 are mounted in the T-shaped apertures in the assembly block 17, nuts 41a, 42a and 43a are screwed on the threaded ends of the bolts. The nuts 41a, 42a and 43a are in the form of short cylindrical rods, and each is provided with a threaded hole passing diametrically therethrough. The threaded ends of the screw bolts 41, 42 and 43 are peened over so that the nuts cannot thereafter be removed. The lengths of the screw bolts are such that when they are fully extended with their heads snugly against the forward surfaces of the intermediate portions of their associated connector bars and the nuts are at the ends of the threaded portions, the ends of the contact portions of the connector bars interfere with the nuts and prevent their turning.

In mounting the connector bar assembly block 17 to the vertical wall 39 of the saddle, the bosses 44, 45 and 46 on the rear face of the block are passed through openings 56, 57 and 58 in the vertical wall 39. The block is then moved against the forward surface of the vertical wall 39 and secured in position thereon by means of fastening screws 54 and 55.

The saddle 38 is then positioned on the shelf 14 with the connector bars 31, 32 .and 33 and their associated .screw bolts aligned with the plug-in openings 35, 36 and 37 in the tubular bus bar insulating enclosures 25, 26 and 27. From this position the saddle is moved by. suitable means, such as by means of a racking screw (not shown) toward the rear of the compartment so that the connector bars and screw bolts enter the openings 35, 36 and 37. The holes 44a, 45a, 46a serve to retain the bolts 41, 42, 43 in parallel relation to the bars 31, 32, 33 respectively, and therefore facilitate entry of the nuts 41a, 42a, 43a, into the apertures 28a, 29a, and 30a respectively. In the final stage of the rearward movement, the nuts 41a, 42a and 43a are at the ends of the screw bolts so that they precede the ends of the connector bars through the slots in the bus bars. When the connector bars and the screw bolts are in place, the screw bolts 41, 42 and 43 are tightened by means of a screwdriver. Since the ends of the connector bars interfere and prevent the nuts from turning, the nuts are drawn forward on the threads of the screwbolts as the bolts are tightened, so that each nut becomes wedged in the space between a flat face of a connector bar and the adjacent edge surface of the slot in the bus bar. As a result of this wedging force, the connector bars are forced and held in tight electrical contact with the edge surfaces of the bus bar slots. If a pulling force is applied to the connector, the wedge-in force is increased and this prevents the connector bar from being pulled out of the slot.

Although a particular embodiment of the invention has been shown and described, it will be apparent that changes and modifications may readily be made by persons skilled in the art without departing from the invention. It is therefore intended that the appended claims shall cover all such changes and modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A connector for making electrical connection to a. bus bar having an opening therein comprising:

(a) a supporting base,

(b) an elongated contact stab supported on said base and projecting therefrom,

(c) a threaded bolt having a first end supported on said base and a free end remote from said base, said bolt extending parallel to and closely spaced from said contact stab,

(d) a wedging member threadedly carried by said bolt adjacent said free end thereof,

(e) means limiting movement of said wedging member in a direction toward said free end of said bolt,

(f) said bolt being slightly longer than said contact stab and said wedging member being dimensioned to interfere with said contact stab whereby rotation of said wedging member about said bolt is prevented by said contact stab,

(g) said contact stab and said wedging member being receivable in said opening of said bus bar when said wedging member is adjacent said free end of said bolt, and whereby rotation of said bolt draws said wedging member toward said supported end of said contact stab and forces said contact stab against the adjacent edge of said opening in said bus bar.

2. A connector as set forth in claim 1 wherein said wedging member comprises a cylindrical member having a tapped hole therethrough in a direction transverse to the longitudinal axis of said cylindrical member, said bolt being threadedly received in said hole.

3. A connector for making electrical connection to a bus bar having an opening therein comprising:

(a) a supporting base of insulating material having front and rear surfaces and having a hole therein extending between said front and rear surfaces,

(b) at least one elongated control stab mounted on said base, and including a portion projecting outwardly from said rear surface,

(c) an elongated threaded bolt carried by said base extending through said hole, said bolt having a headed portion at said front surface of said base and a second threaded portion extending from said rear surface in closely-spaced parallel relation to said projecting portion of said contact stab,

(d) said second portion of said bolt being slightly longer than said projecting portion of said contact stab and having a free end adjacent the free end of said contact stab,

(e) a wedging member threadedly carried by said bolt adjacent said free end thereof, said wedging member having a dimension radially of said bolt greater than the distance between the axis of said bolt and the adjacent surface of said contact stab whereby said contact stab prevents said Wedging member from rotating about said axis of said bolt and rotation of said bolt in a predetermined direction draws said wedging member toward said supported end of said contact stab and Wedges said wedging member in said opening in said bus bar between an edge of said opening and the adjacent surface of said contact stab, and

(f) said hole guiding said bolt to maintain said bolt in said generally parallel spaced apart relation to said contact stab.

4. A connector as set forth in claim 3 wherein said wedging member comprises a cylindrical member having a tapped hole therethrough in a direction transverse to the longitudinal axis of said cylindrical member, said bolt being threadedly received in said hole.

5. In combination (a) a connector bar of electroconductive material having a contact portion, a terminal portion and an intermediate oifset portion,

(b) said bus bar being provided with a slot for receiving the contact portion of said connector bar, and

(c) means for forcing and securing a surface of said contact portion into contact engagement with the surface of an edge of said slot comprising a bolt extending through said intermediate portion and parallel to said contact portion and having a threaded end portion, a nut on said threaded end portion in engagement with the end of said contact portion and restrained thereby from turning, said nut becoming forcefully wedged between a surface of said contact portion and an edge surface of said slot when said bolt is tightened.

6. In combination (a) a base of insulating material having a longitudinal axis,

(b) an opening through said base perpendicular to said longitudinal axis for mounting a connector therein,

(c) a connector bar of electroconductive material mounted in said opening with its longitudinal axis perpendicular to said longitudinal axis of said base of insulating material,

(d) a tubular insulating member having front and rear walls and having an opening in said front wall,

(e) a bus bar supported in said tubular member and extending in the longitudinal direction thereof,

(f) said bus bar being provided with a slot in alignment with said opening in said tubular member for receiving an end of said connector bar,

(g) and means for forcing a surface Olf said connector bar into contact engagement with an edge surface of said slot comprising a bolt projecting through said opening in said base of insulating material and extending parallel to said connector bar with its threaded end projecting through said opening in said tubular member and through said slot and a nut on said threaded end in engagement with the end of said connector bar and restrained by said connector bar from turning, said nut becoming wedged between a surface of said connector bar and an edge surface of said slot when said bolt is tightened.

7. In combination (a) a connector bar of electroconductive material having a contact portion and a terminal portion in spaced apart parallel planes and an intermediate portion in a transverse plane,

(b) said intermediate portion being provided with a fastening aperture,

(c) a tubular insulating member having an opening in its Wall,

(d) a bus bar supported in said tubular member extending in the longitudinal direction thereof,

(e) said bus bar being provided with a slot in alignment with said opening for receiving the contact portion of said connector bar, said slot having two parallel edges, and

(f) means for securing a surface of said contact portion in forceful contact engagement with one of said parallel edges comprising a bolt extending through said fastening aperture and parallel to said contact portion with its threaded end projecting through said opening and through said slot and a nut on said threaded end in engagement with the end of said contact portion and restrained thereby from turning, the combined thickness of said contact portion and said nut being greater than the distance between said parallel edges of said slot thereby to cause said nut to become forcefully wedged between a sunface of said contact portion and an edge of said slot in response to tightening of said bolt.

References Cited by the Examiner UNITED STATES PATENTS 666,744 1/ 1901 Ellis 339-270 1,851,249 3/1932 Hamerly 339-270 1,982,212 11/1934 Hagist 339-250 3,086,191 4/1963 Olashaw 339-22 X FOREIGN PATENTS 1,038,086 6/1953 France.

571,528 3/ 1933 Germany.

EDWARD C. ALLEN, Primary Examiner.

PATRICK A. CLIFFORD, Examiner, 

1. A CONNECTOR FOR MAKING ELECTRICAL CONNECTION TO A BUS BAR HAVING AN OPENING THEREIN COMPRISING: (A) A SUPPORTING BASE, (B) AN ELONGATED CONTACT STAB SUPPORTED ON SAID BASE AND PROJECTING THEREFROM, (C) A THREADED BOLT HAVING A FIRST END SUPPORTED ON SAID BASE AND A FREE END REMOTE FROM SAID BASE, SAID BOLT EXTENDING PARALLEL TO AND CLOSELY SPACED FROM SAID CONTACT STAB, (D) A WEDGING MEMBER THREADEDLY CARRIED BY SAID BOLT ADJACENT SAID FREE END THEREOF, (E) MEANS LIMITING MOVEMENT OF SAID WEDGING MEMBER IN A DIRECTION TOWARD SAID FREE END OF SAID BOLT, (F) SAID BOLT BEING SLIGHTLY LONGER THAN SAID CONTACT STAB AND SAID WEDGING MEMBER BEING DIMENSIONED TO INTERFERE WITH SAID CONTACT STAB WHEREBY ROTATION OF SAID WEDGING MEMBER ABOUT SAID BOLT IS PREVENTED BY SAID CONTACT STAB, (G) SAID CONTACT STAB AND SAID WEDGING MEMBER BEING RECEIVABLE IN SAID OPENING OF SAID BUS BAR WHEN SAID WEDGING MEMBER IS ADJACENT SAID FREE END OF SAID BOLT, AND WHEREBY ROTATION OF SAID BOLT DRAWS, SAID WEDGING MEMBER TOWARD SAID SUPPORTED END OF SAID CONTACT STAB AND FORCES SAID CONTACT STAB AGAINST THE ADJACENT EDGE OF SAID OPENING IN SAID BUS BAR. 